We had a new A/C-heating unit installed in August. A/C worked fine, but when we started using the heater, the breakers started humming and became hot. We called an electrician, the breakers were melted. he replaced the damaged breakers(not the heater breakers. the A/C company came and replaced the heater breakers, which were 50s, with 70s. these melted as well, and the electrician was not happy. this damaged the entire bar on the breaker box.) the entire breaker box has been replaced. the wire to the air handler is the right gauge, and is not damaged, but the breaker still buzzes and gets warm. What could be the problem?

Andy in ATL

01-02-2008 02:58 PM

I think you have a bad connection in the heater or a slow fault to ground in the wiring between the panel and the heater. Would it be "Mission Impossible" to replace the wiring all the way from the panel to the heater?

The wires need "meggered" between the panel and the heater. A megger tests the insulation on the wire by sending high voltage DC current on the wire and measures how much bleeds through. Not all electricians will have a megger.

Heating up breakers occasionally burn houses slap down. So I'd be careful and resolve this quickly.

Andy

oakwood02

01-03-2008 12:46 PM

reply

the wire has been checked, maybe. We're starting to doubt everyone involved in any facet of this. the heater has been checked for loose connections or any defects....We'll go with the "meggering", since the wire to the heater to the box is easy access. But we are at our wit's end, the electrician is blaming the A/C company, the A/C company is blaming the electrician, and nobody seems to know what they're doing. anybody with the slightest idea, please help.

goose134

01-03-2008 06:50 PM

I agree with Andy, it sound like current leaking to ground. My bet is that if your breaker is being cooked like that, your wires aren't far behind. This sounds like classic inductive heating of a raceway, with a bad ground as the main culprit. What type of wiring is it? Romex? Pipe and wire? Flex? Let us know.